Light efficient hair dryer

ABSTRACT

The present invention relates to a professional electric hair dryer comprising a housing containing a brushless electric motor driving a blowing means, an electric heating element and a supply circuit including a direct-current power supply for the brushless motor, said supply circuit being arranged in a housing outside the housing of the hair dryer, which electrically connects said housing to the mains.

The present invention relates to the field of hair dryers. The present invention relates more particularly to a light hair dryer whereof the blowing means are driven by a motor of brushless type and powered by a power supply external to the housing of the hair dryer to reduce the weight of the apparatus.

In recent years, musculo-skeletal disorders (or MSD) of the upper limbs are more prevalent in the world of hairdressing. Some causes of these disorders are tools such as excessively heavy hair dryers. Because of this, hairdressing professionals are more and more demanding lighter hair dryers which combine weight, power and drying efficacy.

A hair dryer using a motor of brushless type is known from the prior art, such as for example patent application EP 1 103 202 A1. The disclosed motor is a motor equipped with a position sensor which knows the position of the rotor relative to the stator. The presence of this Hall effect sensor increases the cost of the motor and the risk of malfunction. According to this document, the motor is fed by the alternating current delivered by mains power and rectified by a diode bridge. The motor used is therefore a fairly heavy motor. Also, the hair dryer described is household apparatus fitted with an axial turbine. The problem with this type of turbine is that it generally does not supply satisfactory aeraulic power.

This hair dryer therefore has the disadvantage of being heavy and having insufficient aeraulic power.

Patent application US 2008/116,753 discloses a hair dryer with a motor of brushless type with internal rotor without specifying whether this motor is with or without sensor. This application describes a compact hair dryer fed by a phase-angle control circuit and zero detection placed inside the dryer. But the proposed solution is not safe. In fact, after hashing, the signal is rectified by a diode bridge then filtered by means of a condenser to obtain the closest possible signal to a continuous signal. For the output signal to be smooth, the circuit would need a high-capacity condenser.

There is a problem if this electrochemical condenser explodes as a result of overvoltage or of the latter ageing. Due to its high capacity, the explosion could be violent. This explosion could also be accompanied by electrolyte projection and/or the dryer bursting into flames. This can prove to be highly dangerous for users (for example the hairdresser and the client).

The aim of the present invention is to rectify at least some disadvantages of the prior art by proposing especially a hair dryer which is light, safe and performing or offers the maximum comfort of use with minimum risk for the user.

This aim is achieved by an electric hair dryer, characterised in that it comprises both a hair dryer housing, containing an electric motor of brushless type driving blowing means, a heating element electric and also a supply circuit comprising a power supply with direct current for the motor of brushless type, this supply circuit being arranged in a housing external to said housing of the hair dryer and electrically connecting the latter to the mains.

According to another particular feature, the supply circuit comprises a switch-mode power supply low-voltage.

According to another particular feature, the mains voltage and the output of the supply circuit are galvanically insulated.

According to another particular feature, the galvanic insulation is achieved by at least one optoelectronic element.

According to another particular feature, the hair dryer is connected electrically to the supply circuit by a cord comprising three wires due to referencing of the continuous output signal of the supply circuit relative to one of the poles of the mains voltage.

According to another particular feature, the hair dryer comprises control means for controlling at least the heating circuit and supplying speed setpoints to the motor of brushless type, whereof at least one interrupter coupled with a magnet moves near magnetic contactors so as to switch the latter together or individually.

According to another particular feature, the hair dryer comprises control means for controlling at least the heating circuit and supplying speed setpoints to the motor of brushless type, whereof at least one interrupter selects a speed of the motor and simultaneously modulates the current passing through the heating element as a function of the selected speed so as to retain constant heat.

According to another particular feature, the motor of brushless type is a motor with inner armature and outer inductor.

According to another particular feature, the motor of brushless type is a motor of sensorless type with a control circuit determining the position of the rotor by measuring the current induced by the magnets on the non-powered windings.

According to another particular feature, the axis of the motor is connected to the armature-inductor pair at least by means of two rollers arranged near the ends of this armature-inductor pair along said axis of the motor.

According to another particular feature, the armature and the inductor are mounted concentric in a motor housing and about the axis to which the inductor is connected.

According to another particular feature, the external power supply housing comprising the supply circuit is arranged to act as support to the hair dryer.

Another aim of the present invention is to propose a hair dryer whereof the motor is stable.

This aim is achieved by an electric hair dryer with motor of brushless type comprising a motor of brushless type comprising an axis and an armature-inductor pair, characterised in that the axis of the motor is connected to the armature-inductor pair at least by means of two rollers arranged near the ends of the armature-inductor pair along the axis of the motor.

According to another particular feature, the armature and the inductor are mounted concentric in a motor housing and about the axis to which the inductor is connected.

According to another particular feature, the motor comprises a rotor mounted in rotation about a stator and a casing, in the form of a bell, enclosing the stator and the rotor, with a roller receiving the axis of rotation driven by the rotor and connected by one of its ends to the turbine upstream of the motor.

Other particular features and advantages of the present invention will emerge more clearly from the description hereinbelow, given in reference to the attached diagrams, in which:

FIG. 1 illustrates a sectional view of a hair dryer according to some embodiments of the invention.

FIGS. 2 a and 2 b illustrate respectively an exploded view and an assembled view of a motor of brushless type according to some embodiments of the invention.

FIG. 3 illustrates a cabling diagram of the electronic circuit controlling the hair dryer according to some embodiments of the invention.

FIG. 4 a presents the operating modes of a bipolar interrupter of all-or-nothing type used in some embodiments of the invention.

FIG. 4 b presents the operating modes of a progressive bipolar interrupter used in some embodiments of the invention.

FIG. 5 illustrates a block diagram of a supply circuit of the hair dryer according to some embodiments of the invention.

FIG. 1 illustrates an embodiment of a professional electric hair dryer according to the invention. The electric hair dryer comprises, as is known per se, a hair dryer housing which is made of, for example and non-limiting, plastic material, and comprises a handle (2) and a body (1). The terms dryer or hair dryer are used interchangeably in the present application to designate the same device.

In some embodiments, the body (1) comprises an input (13) and an output (14) for air. A motor (10), of brushless type, which drives blowing means (11) projecting air from the air intake (13) to the output air (14) is placed in the body (1). Preferably, the blowing means will be a centrifugal turbine, preferably arranged upstream of the motor relative to the direction of circulation of the air in the hair dryer. An advantage of a centrifugal turbine, for example relative to an axial turbine, is that it is capable of supplying substantial aeraulic power, especially satisfying the needs of a hair dryer, in particular a professional hair dryer pour which it is often preferable to have more power than for a standard hair dryer. For example, at equivalent pressure, the centrifugal turbine has greater airflow than an axial turbine. Also, an axial turbine is not capable of delivering airflow with pressure sufficient even if it delivers considerable airflow whereas a centrifugal turbine has a pressure curve as a function of the flow which has good pressure and good flow at the same time. Considerable airflow, at output of the hair dryer, is very important for drying hair rapidly because the airflow leaving the dryer must be at high speed.

According to a particular feature of the invention, the motor used is of brushless type. An advantage of this type of motor is that it has a yield clearly superior to that of a brush motor; this is partly due to the absence of mechanical and electrical losses associated with brushes. Another advantage of motors of brushless type is their lifetime. In fact, the lifetime of brush motors is associated with the lifetime of carbons. Because of this, the absence of brushes in motors of brushless type gives them an almost unlimited lifetime.

According to another particular feature, the motor of brushless sensorless type is a direct-current motor. With using a direct-current brushless motor, lighter than some known motors (such as for example that from application EP 1 103 202 A1 described in the preamble), the hair dryer is capable of supplying good aeraulic power without need for a motor which is too heavy and/or bulky. According to various advantageous embodiments, the voltage of this motor (10) is low and of the order of 10 to 80 volts, preferably 20 to 60, ideally 42V. An advantage of a motor (10) of low-voltage brushless type relative to mains voltage, for example 230V, is that it is easier to wind. In fact, to have a small and compact motor with voltage of 230V a very fine wire would have to be used, which would make the motor difficult to wind and would increase the retail price. However, using a brushless motor is particularly advantageous in terms of efficacy and weight of the hair dryer. In fact, to have the same useful power as a brushless motor, a universal motor would need to weigh of the order of double or triple that of a brushless motor. However, the preference in the present invention is to use low voltage which is not the lowest possible because, for motors with continuous currents such as brushless motors, the choice of low voltage also impacts on dimensions and weight. In particular, field effect transistors (mosfet, for “metal-oxide-semiconductor field-effect transistor”) which conduct the switching of a brushless motor, must be greater and better cooled if the voltage used is lower (at equal power). Direct current with low voltage which is not too low to avoid having to provide too large mosfets is preferably chosen in the present invention. Continuous voltage preferably between 20 and 60, ideally 42V, is a preferred compromise for reasons of size of components, weight and heat.

It is understood from the above that a brushless motor with direct current is selected to produce a powerful hair dryer of reduced weight. It is also understood that a supply circuit (31) with direct current is therefore needed to feed this motor. This type of power supply generally has the disadvantage of being bulky and heavy, especially more than a single transformer. The presence of this power supply with direct current is therefore an obstacle to some aims of the present invention. Therefore, in some preferred embodiments of the invention the power supply of the hair dryer is shifted to an external power supply housing (3) on the dryer to reduce the weight of the latter, in addition to the advantages already mentioned in the preamble of the present application, such that shifting the condenser improves safety. This external power supply housing (3) comprises the supply circuit (31) intended to provide the energy necessary for the motor (10) of the hair dryer. This produces a light and effective hair dryer by means of the brushless motor the supply circuit of which does not counteract gains in weight (i.e. gain in lightness) and bulk (i.e. space gain) resulting from use of such a motor.

On the other hand, in some preferred embodiments the motor (10) is of the sensorless type. An advantage of a motor (10) of this type is that it needs no system for discovering the position of the rotor relative to the stator. This economises for example on a position sensor and therefore reduces both costs and weight. This also eliminates the risk of breakdown and therefore eliminates or reduces maintenance costs.

Because this motor (10) does not have a position sensor, it accordingly needs a special speed controller (18) for switching the power supply of its phases. By way of non-limiting example, a TOSHIBA TB6575FNG controller could be used. To determine the position of the rotor, the speed controller (18) will measure, in the three phases of the motor (10), the counter-electromotive force generated by displacement of the permanent magnets (63) in front of these spools (51) and deduce torque to trigger switching of the three phases. The speed controller (18) needs precise power supply voltage. This power supply voltage will be provided by a supply circuit (31) comprising a switch-mode power supply. The speed controller (18) will preferably be placed most closely to the motor (10). The speed controller (18) could be mounted for example on a printed circuit board (15) placed under the motor (10).

The present invention is presented here with a motor of brushless and sensorless type but could also operate with a motor of brushless type with sensor. In these embodiments, a controller adapted to the motor of brushless type with position sensor would be used to control said motor.

The supply circuit (31) is preferably formed by a switch-mode power supply fed by the mains. Examples of advantages of the switch-mode power supply are its low weight and its small bulk relative to linear power supplies. This is because the transformer of the switch-mode power supply operates at a higher frequency than that of the mains, which helps reduce its size and therefore its weight. Also, because the power dissipated in the electrotechnical component used in switching is lower than when it is used in linear mode, the switch-mode power supply also has the advantage of providing a much better yield than linear power supplies. According to a non-limiting embodiment, the switch-mode power supply is of “flyback” type. An advantage of such assembly is that it needs few components and has economical architecture for low powers. Also, switch-mode power supplies provide very precise voltage. The controllers used, especially those required by brushless sensorless motors, need to be fed by very precise voltage. It is understood therefore that the switch-mode power supply is particularly preferred in the case of these brushless sensorless motors.

Hair dryers generally comprise at least one heating element (12), such as at least one resistor for example, for heating air blown by the blowing means (11) and for making drying easier due to the resulting hot airflow. The airflow is preferably reheated by a heating element through which electric current flows. The heating element can, for example, comprise several heating resistors to vary the temperature, for example by switching the resistors by at least one interrupter, for example an interrupter with multiple positions. In some embodiments detailed in the present application, the switching of various resistors is dependent on the speed of rotation of the motor. These heating means or heating elements (12) generally operate on mains supply, that is, alternating current. It is understood therefore that the hair dryer needs two voltages, continuous voltage for supplying, inter alia, the motor (10) and mains voltage for supplying the heating element, for example.

In some particularly advantageous embodiments, the supply circuit is preferably arranged such that the output of the power supply and the mains voltage are insulated galvanically. This insulation references the output voltage relative to one of the poles of the input voltage. This dispenses with a wire in the cable connecting the power supply housing (3) and the hair dryer. So, in some embodiments, the output signal of the supply circuit (31) is referenced relative to one of the poles of the input signal. This particular feature has only three wires at output of the supply circuit, and combines the direct current power supply with the mains power supply. This allows the cable (22) connecting the external power supply housing (3) on the dryer to have only three wires and therefore be easier to make (due to conventional use), to be lighter and less rigid than if it were to have more wires (especially four) as a power supply not comprising these technical characteristics would need. Also, and preferably, the wires of the cable (22) will be multi-strand so as to add greater flexibility to the cable (22).

It is understood also from the above that the present invention preferably uses continuous power supply to feed the motor and the mains current to feed the heating element (12). These two separate sources of power supply advantageously provide for the power supply of the heating element (12) to be cut while the motor (10) is left on voltage and therefore blows cool and not lukewarm air. Some embodiments capitalise on this advantage of two separate power supplies, for example as detailed hereinbelow.

In some embodiments, the body (1) also contains at least one printed circuit board (15) comprising the electronic components for controlling the motor (10). This printed circuit board can comprise or be associated with control means. For example, in some of these embodiments a second printed circuit board (15′) is placed in the handle (2) of the hair dryer to at least control the heating circuit and give the speed setpoints to the motor of brushless type via a set of interrupters placed on this circuit (15′).

In some embodiments, control means of the hair dryer are arranged in the handle (2) of the hair dryer, which makes their access advantageously easy. These means comprise at least one control element (SW1, SW2, SW3, SW4, SW5), such as for example an interrupter or a push button for controlling at least one function of the hair dryer.

In reference to FIG. 3, the control means and in particular the control electronics used in some embodiments of the hair dryer will be presented.

According to the embodiment presented in FIG. 3, the control means comprise 5 control elements, formed by 5 interrupters (SW1 to SW5). It is understood from the following that all or some of these control elements can be provided according to which all or some of the functions they control are provided. Similarly, these examples can be replaced by known equivalents, even though they are often advantageous, as detailed hereinbelow, and therefore preferably used. So, the terms “first”, “second”, “third”, “fourth” and “fifth” must not be interpreted as being limited.

In some embodiments, a first interrupter (SW1) of type bipolar functioning in all-or-nothing mode is provided. This interrupter (SW1) sends voltage to the hair dryer. When the interrupter (SW1) is open, no current circulates and when it is closed the wires in which the phase and the direct current circulate are connected electrically to the circuit.

In some embodiments, at least one interrupter is provided to manage the temperature of the air. As mentioned earlier, in some embodiments the temperature is switched as a function of the speed of rotation. Preferably, two interrupters SW2 and SW3 are provided, such as for example bipolar interrupters operating in progressive mode. In reference to FIG. 4 b, these interrupters (SW2, SW3) have three positions. A first position (0) corresponds to the case where the two poles are open. The second position (1) corresponds to the case where only one pole, the pole connecting ports 1 and 1 a, is closed and the third position corresponds to the case where the two poles are closed.

The second interrupter (SW2) allows modification of the power of the heating element. When the interrupter (SW2) is open no current circulates in the heating element for blowing cold air. When just the first pole (1-1 a) of the interrupter (SW2) is switched, a resistor (Rc) is put into series with the resistors (R1, R2, R3), connected in parallel, of the heating element (12), which decreases its power. When the two poles of the interrupter (SW2) are switched, the resistor Rc is short-circuited, enabling more current to circulate in the heating element and therefore produce more heat.

The third interrupter (SW3) is formed by a progressive bipolar interrupter with three positions coupled to a magnet (19) moving above of two magnetic contactors, such as for example leaf switches (ILS or Reed switch). This particular feature controls two progressive bipolar interrupters simultaneously without any excessive resistance being felt by actuating the control button. This avoids fatiguing the thumb of the user when changing the speed of the dryer. Another advantage of this configuration, relative to a configuration with two bipolar interrupters in parallel, is that it reduces the bulk occupied by the two interrupters.

This interrupter (SW3) varies the speed of the motor (10) of the hair dryer and simultaneously switches the heating elements to adapt the heat to this speed.

The variation in speed of the motor (10) is achieved by varying the voltage at the terminals of the controller (18). The interrupter (SW3) also modulates the current passing through the heating element (12) as a function of the selected speed. To keep constant heat, when a low speed is selected a low current will pass through the heating element (12) and when a high speed is selected a higher current will pass through the heating element (12). This modulation of the current is achieved by varying the number of resistors (R₁, R₂, R₃) parallel to the heating element (12).

Another particular feature of this assembly is enabling galvanic insulation between the interrupter (SW3) operating on mains voltage (for example 230V 50 Hz or 120V 60 Hz) and the speed setpoint of the controller (18) operating at continuous low voltage, such as for example and non-limiting, 5V.

When the interrupter (SW3) is in position 0, the two contacts of the interrupter (SW3) are open and the magnet (19) is moved away from the two leaf switches (ILS1, ILS2) which remain in open circuit. When the interrupter (SW3) is in position 1, only the first contact of the interrupter (SW3) is closed and the magnet (19) is located above the first leaf switch (ILS1), which closes its contact, with the second interrupter (ILS2) remaining in open circuit. When the interrupter (SW3) is in position 2, the two contacts of the interrupter (SW3) are closed and the magnet (19) is now between the two leaf switches (ILS1, ILS2), closing these two contacts.

In some embodiments, the dryer can also comprise, inside the body (1), a negative ion generator (16, 17) for smoothing hair. The negative ions generated neutralise the static electricity generated during hairdressing and/or hair drying. The printed circuit board or printed circuit boards could comprise, or be linked to, control means for the ion generator. For example, in some embodiments, a fourth interrupter (SW4) is provided which is for example unipolar (for example, of button type). Pressing on this interrupter (SW4) sends voltage to the ion generator (17) independently of the other elements. According to a variant embodiment, the negative ion generator (16, 17) is permanently supplied with voltage and action on this interrupter coupes its power supply to create a hairstyle with more body. The ion generator (16, 17) is for example and of non-limiting formed by a needle (17) fed by a compact power supply (16), of small dimensions and of high voltage, placed inside the body of the hair dryer. According to a non-restrictive embodiment the ion generator (16, 17) can for example be created by a power supply delivering voltage of around 4 KV at the tip of a needle (17).

Pressing on the interrupter (SW4) also feeds and illuminates an electroluminescent diode (LED) acting as pilot light for this button (SW4).

In some embodiments, a fifth interrupter (SW5) is provided which is for example an interrupter button of “normally closed” type. Pressing on this interrupter opens the supply circuit of the heating element and blows cold air when the motor is powered. Such a function is possible because the power supply of the motor (10) of the hair dryer is independent of the heating element (12).

In fact, in conventional terms, hair dryers with continuous motor use the resistor or the resistors of the heating element to lower the mains voltage to feed said motor after straightening and filtering. Because of this, current is always running through the heating element when the motor of the hair dryer is on and therefore this heating element is never really cold. With such an embodiment, it is impossible to cut off the power supply of the heating element without cutting off the power supply of the motor of the hair dryer and therefore it is impossible to blow completely cold air.

By way of difference, the present invention utilises continuous power supply to feed the motor and the mains current to feed the heating element (12), in particular a supply circuit (31) external to the hair dryer, as indicated previously. These two separate power supply sources advantageously cut off the power supply of the heating element (12) while leaving the motor (10) supplied by voltage and therefore blowing cold air which is not lukewarm.

These control means (SW1 to SW5) are preferably placed on a printed circuit board (15′), in turn placed in the handle (2) of the hair dryer. Of course, other embodiments are possible. In some embodiments, these control means could be placed in the handle (2) and connected by cables to the elements to be controlled. According to another embodiment, some of the control means could be placed on a printed circuit board and others connected by cables to the elements to be controlled.

In reference to FIG. 5, a low-voltage supply circuit (31) used in some embodiments of the hair dryer will be presented. This figure illustrates a block diagram of a switch-mode power supply, preferably used in the present invention as indicated and for reasons specified previously.

A first straightening and filtering block (B1) is fed by alternating current from the mains. This voltage could, for example, have an effective value of 230V and a frequency of 50 Hz or an effective value of 110V and a frequency of 60 Hz. Once filtered and rectified, the continuous electric signal is then cut in a hashing block (B2). The voltage is then lowered using the energy transfer block (B3). This block essentially comprises a transformer. Once it is lowered, the voltage is then filtered and rectified in a secondary straightening and filtering block (B4). It is evident that the energy transfer block (B3) also ensures galvanic insulation between the cutting block (B2) and that of secondary straightening and filtering (B4) by way of its transformer.

Some of the output voltage is taken and moves to a comparison block (B5). The aim of this block is to ensure that the output voltage is definitely equal to the preferred output voltage. In the event where the output voltage is different to that of the set voltage, the comparison block (B5) sends a signal to the hashing block (B2) to modulate the hashing of the voltage and produce continuous setpoint voltage. Another advantage of this servo loop is that it produces the preferred output voltage irrespective of the voltage applied at input of the switch-mode power supply. This creates an international power supply without concern for the voltage of the network to which the power supply is connected and without having to shift a switch to 230V or 120V.

In some embodiments, the comparison block (B5) is insulated from the hashing block (B2) by an optoelectronic element. This optoelectronic element can be an optocoupler such as for example and non-limiting a phototransistor or an opto-triac.

The supply circuit is preferably arranged such that the output of the power supply and the mains voltage are insulated galvanically, as mentioned previously. This insulation is created here by the transformer present in the energy transfer block (B3) and by the optoelectronic element of the insulation block (B6) of the servo loop. The interest in this particular feature is that it references the output voltage relative to one of the poles of the input voltage. This does away with a wire in the cable connecting the power supply housing (3) and the hair dryer.

In some embodiments, the motor of brushless type (10) is connected by cable in triangular assembly, the spools are therefore mounted in series and have strong impedance. The motor (10) will need low voltage and high current. By way of example and according to a non-restrictive embodiment, the motor (10) consumes current of around 2.4 A for voltage of around 42V. With such a current, the wires of the cable (22) must have a cross-section of at least 0.75 mm². The fact of being able to do without a wire in the cable (22) helps considerably reduce the weight of the latter. This also produces a less rigid cable. Omitting a conductor in the cable (22) also utilises a cable currently used in industry as opposed to a cable with four conductors. The effect of this is a reduction in the cost of the dryer.

In reference to FIG. 2, the electric motor (10) of brushless type used in some embodiments will be described. This motor (10) comprises a rotor (6) mounted in rotation about a stator (5) and a casing (7), in the form of a bell, enclosing the stator (5) and the rotor (6).

In these embodiments, the stator (5) comprises a sheet metal stack (510) and different windings (51), forming the armature fed by a connector (56). According to a non-restrictive embodiment the stator (5) comprises nine windings (51) distributed uniformly in three phases. Each phase therefore comprises 3 windings (51) mounted in series. The three phases could for example be mounted in a triangular configuration, as illustrated in FIG. 3, or in a star configuration. An advantage of the triangular configuration is that it is easier to wind since there is no way to attach a mid-point. The sheet metal stack (510) is mounted about a tube (53) attached to a plate (54), the tube (53) being mounted perpendicularly on said plate (54). The plate (54) comprises a connector (56) fitted with three contacts, each of the contacts being connected to a different phase of the stator. The plate (54) also comprises a roller (52) receiving the axis of rotation (61) driven by the rotor and connected by one of its ends to the turbine upstream of the motor. The roller (52) is blocked against the plate (54) by an insulator (540). The rollers (52, 72 hereinbelow) are for example, ball bearings or needle bearings or of any other type. The roller (52) is mounted perpendicularly to the tube (53) on the face of the plate (54), opposite that on which the windings (51) are mounted. According to an embodiment, the plate comprises longitudinal openings (55) passing through the thickness of the plate (54).

In some embodiments, the rotor (6) or inductor can be formed by a cylindrical element (62), for example, in the form of a bell, mounted fixed on an axis (61), forming the axis or the shaft (61) of the motor (10), passing through the axis of revolution of the cylindrical element (62). An end of the shaft motor (61) is designed to be inserted into the roller (52) placed on the plate (54) of the stator (5). Permanent magnets (63), for example, of rectangular form, are adhered parallel to the axis of rotation, on the inner face of the longitudinal part of the cylindrical element (62) of the rotor (6). These magnets are placed so as to alternate north south. Each permanent magnet (63) is identical. During manufacture and because of the tolerances on the dimensions of the magnets (63), magnets of slightly different weight could be mounted. This difference in weight will cause imbalance on the rotor. During rotation, an imbalance will produce vibrations and cause a problem for the user. Balancing masses will be placed inside the rotor (6) to balance the rotor (6) and therefore reduce resulting problems.

In some embodiments, the inductor will comprise 6 evenly spaced permanent magnets (63). The cylindrical element (62) could also comprise openings (65) on one of these radial faces forming the bell.

In some embodiments, one end of the axis (61) of the rotor (6) could be cut out over a certain length. In this embodiment the ball bearing (52), placed on the plate (54) of the armature (5), will have an inner diameter less than the diameter of the shaft to attach the shaft motor (61) of the inner cage of the roller (52) and enable rotation of the rotor (6) relative to the external cage of the roller (52) which is attached to the plate (54).

In some embodiments, once it is mounted on the armature (5), the body of the cylindrical element (62) of the inductor (6) is not stopped on the plate (54) of the armature (5), creating a space between said plate (54) and the cylindrical element (62). In this embodiment, the openings (75), of the lateral surface of the cylindrical element (62) are made such that the position of the space corresponds to the position of the openings (75).

In conventional terms, the motors of brushless type are so-called external rotor motors and are held only by one plate bearing the stator. Rollers (52, 72) are placed at the level of the stator or armature and the axis of the rotor nests in these rollers. A turbine is then fixed on the rotor. The disadvantage of this assembly is that the turbine is now in overhang, whereby the slightest imbalance of the turbine makes the whole assembly vibrate. This is highly problematic for the user and merely increase the work burden.

In some embodiments designed to prevent this overhang and accordingly prevent vibration problems, the axis of the motor is connected to the armature-inductor pair at least by means of two rollers arranged near the ends of the armature-inductor pair along the axis of rotation of the motor. Also, in some embodiments, the armature and the inductor are mounted concentric in a motor housing and about the axis of the motor to which the inductor is connected. A casing (7), for example and non-restrictively in the form of a bell, is provided for example assembled about the rotor (6). This casing is set by the free end of the casing in a peripheral shoulder (57) of the plate (54). At the centre of the part forming the bottom of the casing is mounted a roller (72). This roller (72) is intended to receive the other end of the shaft motor (61). This embodiment keeps the motor (10) radially in position, in the dryer, on two parts to the right of the rollers (52, 72) or over the entire length of the motor (10), which would not be possible with a configuration having an external rotor. The casing (7) is preferably made of aluminium or any other thermally conductive material so as to dissipate heat from the motor (10). Another advantage of the use of the aluminium, for making the casing (7), is the gain in weight (i.e. gain in lightness) due to the low volumic mass of this material. Openings (75) are also made in the casing (7). These openings (75) could for example be made on the face bearing the ball bearings (72) and/or on the lateral part. These openings (75) cooperate with the openings (65) of the rotor (6) and those (55) of the stator (5) so that airflow enters the motor (10) to cool it when the rotor (6) turns.

It is understood therefore from this description of the motor preferably used in the present invention that this produces a particularly advantageous arrangement of the motor in that it is stable. In fact, it avoids overhang, which improves its stability and prolongs its lifetime. Because such an arrangement is particularly advantageous and is not dependent on the other characteristics described in the present application (especially the external power supply circuit or the control means), it is understood that a hair dryer can be provided comprising such an arrangement of the motor, and that it does or does not comprise the other means or characteristics described here. In this way, the invention also relates to a hair dryer with brushless motor in which the axis of the motor is connected to the armature-inductor pair at least by means of two rollers arranged near the ends of the armature-inductor pair along the axis of rotation of the motor. In some embodiments of this type of hair dryer, the armature and the inductor are mounted concentric in a motor housing and about the axis of the motor to which the inductor is connected. For example, as indicated hereinabove, this motor (10) comprises a rotor (6) mounted in rotation about a stator (5) and a casing (7), in the form of a bell, enclosing the stator (5) and the rotor (6). The stator is mounted, for example via a plate (54), by means of a roller (52) receiving the axis of rotation (61) driven by the rotor and connected by one of its ends to the turbine upstream of the motor. The bottom of the casing is mounted on a roller, which keeps the motor (10) radially in position, in the dryer, on two parts to the right of the rollers (52, 72) or over the entire length of the motor (10). Other variants clearly derive from the preceding description of the motor.

In some embodiments, the air intake (13) can also comprise a grid so as to prevent hair or dust from being sucked in by the dryer during use.

In some embodiments of the invention, an extender or nozzle (also called concentrator) could be mounted on the air outlet (14) of the hair dryer to channel the discharging airflow. Another advantage of a nozzle on the air outlet of the hair dryer is that by modifying its geometry it modifies the pressure of the output airflow. Giving this nozzle an optimal shape will boost pressure optimally for airflow of given output.

In some embodiments of the invention, an extender or nozzle (also called concentrator) could be mounted on the air outlet (14) of the hair dryer to channel the discharging airflow. Another advantage of a nozzle on the air outlet of the hair dryer is that by modifying its geometry it modifies the pressure of the output airflow. So, giving optimal form to this nozzle increases the pressure optimally for a given output air rate.

The present application describes various technical characteristics and advantages in reference to the figures and/or various embodiments. The person skilled in the art will understand that the technical characteristics of a given embodiment can in fact be combined with characteristics of another embodiment unless otherwise specified or unless it is evident that these characteristics are incompatible. Also, the technical characteristics described in a given embodiment can be insulated from other characteristics of this mode unless otherwise specified and any structural adaptations necessary for combinations or insulation of characteristics will be within the reach of the person skilled in the art by way of the functional considerations provided in the present application.

It must be evident for the person skilled in the art that the present invention allows embodiments in numerous other specific forms without going beyond the field of application of the invention as claimed. Consequently, the present embodiments must be considered by way of illustration, but can be modified in the field defined by the scope of the attached claims, and the invention must not be limited to the details given hereinabove. 

1. An electric hair dryer, wherein it comprises both a hair dryer housing, containing an electric motor of brushless type driving blowing means, an electric heating element and also a supply circuit comprising a power supply with direct current for the motor of brushless type, this supply circuit being arranged in a housing external to said housing of the hair dryer and electrically connecting the latter to the mains.
 2. The hair dryer according to claim 1, wherein the supply circuit comprises a switch-mode power supply low-voltage.
 3. The hair dryer according to claim 1, wherein the mains voltage and the output of the supply circuit are galvanically insulated.
 4. The hair dryer according to claim 3, wherein the galvanic insulation is achieved by at least one optoelectronic element.
 5. The hair dryer according to claim 3, wherein it is connected electrically to the supply circuit by a cord comprising three wires due to referencing of the continuous output signal of the supply circuit relative to one of the poles of the mains voltage.
 6. The hair dryer according to claim 1, wherein it comprises control means for controlling at least the heating circuit and providing speed setpoints to the motor of brushless type, whereof at least one interrupter coupled with a magnet moves near magnetic contactors so as to switch the latter together or individually.
 7. The hair dryer according to claim 1, wherein it comprises control means for controlling at least the heating circuit and providing speed setpoints to the motor of brushless type, whereof at least one interrupter selects a speed of the motor and simultaneously modulates the current passing through the heating element as a function of the speed selected so as to retain constant heat.
 8. The hair dryer according to claim 1, wherein the motor of brushless type is a motor with inner armature and outer inductor.
 9. The hair dryer according to claim 1, wherein the motor of brushless type is a motor of sensorless type with a control circuit determining the position of the rotor by measuring the current induced by the magnets on the non-powered windings.
 10. The hair dryer according to claim 1 wherein the axis of the motor is connected to the armature-inductor pair at least by means of two rollers arranged near the ends of this armatureinductor pair along said axis of the motor.
 11. The hair dryer according to claim 1, wherein the armature and the inductor are mounted concentric in a motor housing and about the axis to which the inductor is connected.
 12. The hair dryer according to claim 1, wherein the external power supply housing comprising the supply circuit is arranged to act as support to the hair dryer.
 13. An electric hair dryer with motor of brushless type comprising a motor of brushless type comprising an axis and a armature-inductor pair, wherein the axis of the motor is connected to the armatureinductor pair at least by means of two rollers arranged near the ends of the armature-inductor pair along the axis of the motor.
 14. The hair dryer according to claim 13, wherein the armature and the inductor are mounted concentric in a motor housing and about the axis to which the inductor is connected.
 15. The hair dryer according to claim 1, wherein the motor comprises a rotor mounted in rotation about a stator and a casing, in the form of a bell, enclosing the stator and the rotor, with a roller receiving the axis of rotation driven by the rotor and connected by one of its ends to the turbine upstream of the motor. 